The present invention relates, in general, to communication systems and more particularly to channel management in communication systems.
In communication systems, such as cable telephony systems, having several remote units communicating through a head-end office, communication channel management is critical to maintain high quality service. Information is typically transmitted through communication channels using radio frequency carriers. A carrier may contain one or more channels depending on the type of communication system. The head-end office typically contains several receivers for receiving the several different carriers. Noise at any carrier frequency may distort the information and decrease the quality of service for a channel on that particular carrier. To increase quality of service, systems manage the channels by monitoring the carriers and using only the higher quality channels for transmitting information.
One attempt at managing channels in a communication system includes measuring channels on carriers that are currently being used for communication. A quality measurement procedure is performed on a channel on a particular carrier to obtain quality information on the carrier. However, since at least one channel is used for communication (transmitting user data) on that particular carrier, the receiver must remain tuned to the frequency of that carrier. Systems typically have carriers that are not used for communication, referred to as idle carriers. In systems that measure the quality of a carrier or channel which contains communication information, the idle carriers can not be measured with the receivers that are receiving communication information.
Another attempt at managing channels includes using a dedicated receiver for scanning idle channels. In systems that have idle channels available, a dedicated receiver may be used to measure the quality of a communication channel. The dedicated receiver is tuned to each idle channel in turn and each channel is measured for quality. The channels are then allocated to provide communication links based on the quality of each channel. In these systems, the dedicated receiver is used only for measuring the quality of the communication channels. These systems are inefficient since the resources of an entire receiver must be dedicated to measuring idle carriers. The added expense of a communication system in providing an extra receiver at each head-end office is significant.
Therefore, conventional systems either cannot measure idle carriers or do not efficiently utilize the hardware at the head-end office and there exists a need for an efficient cable management method and apparatus that can fully utilize the receivers at the head-end office for communication while monitoring the quality of idle channels.